Catalytic heater

ABSTRACT

A catalytic heater having a catalytic bed connected to a frame, incorporates an improved ignition and fuel shutoff system. A needle valve controlling the discharge of fuel onto the catalytic bed for oxidation includes a thermosensitive needle which is preheated by a pilot light. Upon reaching a predetermined temperature, the thermosensitive needle disengages its valve seat to allow fuel from the fuel supply to discharge onto the catalytic bed where oxidation thereof occurs. Upon cooling of the catalytic bed the thermosensitive needle resets to abrogate the discharge of fuel onto the catalytic bed and thereby prevent leakage of fuel.

United States Patent Richards May 16, 1972 s41 CATALYTIC HEATER FOREIGNPATENTS OR APPLICATIONS [72] Inv n r: J M-Ri r .T l ,Okl 1,136,8291/1957 France ..431/329 73 Assi nee: Nu ar Manufacturin C Inc., T ls 1 gg 8 u a Primary ExaminerCharlesJ.Myhre Att0rney-Head & Johnson [22]Filed: June 29, 1970 Appl. No.: 50,557

Schantz ..l26/92 X- Y ABSTRACT A catalytic heater having a catalytic bedconnected to a frame, incorporates an improved ignition and fuel shutoffsystem. A needle valve controlling the discharge of fuel onto thecatalytic bed for oxidation includes a therrnosensitive needle which ispreheated by a pilot light. Upon reaching a predetermined temperature,the therrnosensitive needle disengages its valve seat to allow fuel fromthe fuel supply to discharge onto the catalytic bed where oxidationthereof occurs. Upon cooling of the catalytic bed the therrnosensitiveneedle resets to abrogate the discharge of fuel onto the catalytic bedand thereby prevent leakage of fuel.

4 Claims, 2 Drawing Figures PATENTEDMAHBIM 3,662,737

sum 1 or 2 llVl/E/VTOR.

JOE M. RICHARDS ATTORNEYS PATENTEDMAY 16 m2 3; 662 737 SHEET 2 UF 2l/VVE/VTOR. JOE M. RICHARDS wfm ATTORNEYS CATALYTIC HEATER-1 BACKGROUNDOF'TI-IE INVENTION This invention relates to heaters andmoreparticularly to a catalytic heater having an improved ignition andfuel shutoff system.

Presently manufactured catalytic heaters usually consist of Presentlymanufactured catalytic heaters have two main disadvantages. First, thepreheating of the bed to reaction temperature, that is the temperatureat which the fuel oxidizes without flame, must be done by sprinklingthecatalytic bed with an external fuel and lighting the same. This resultsin a flaming up of the catalytic bed momentarily until the bed reachesreaction temperature. Secondly, presently manufac-. tured catalyticheaters do not have any safety shutoff of the fuel supply in the eventof-inadvertent reduction of the catalytic bed temperature to a valvebelow the reaction temperature.

It is thereforean object of this invention to present a catalytic heaterhaving overcome the aforementioned difficulties of presentlymanufactured catalytic heaters.

It is a further object of this invention to present a. catalytic.

heater having an improved ignition system wherein the catalytic bed ispreheated before introduction of the hydrocarbon fuel onto the bed.

It is still a further object of this invention to present a catalyticheater incorporating an automatic fuel shutoff apparatus. It is still afurther object of this invention to present a catalytic heaterpivotallycarried by a frame and having storage space for spare fuel reservoirs.

SUMMARY OF THE INVENTION Generally the catalytic heater of thisinvention comprises a framehaving pivotally connected thereto acatalytic bed carrying a catalyst of platinum. The catalytic bed isinterconnected to a hydrocarbon fuel supplywhich discharges the fuelupon the catalytic bed for non-flammable oxidation thereof. Anignition'and fuel shutoff system inserted between the fuel supply andthe catalytic bedincludes a-needle valve which is controlled by athermosensitive bi-metallicelement which in turn controls and regulatesthe flow of fuel onto the catalytic bed.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an isometric view showingthe'catalytic heater of this invention.

FIG. 2 is a cross-sectional view of the catalytic heater of thisinvention taken along lines 2-2 of FIG. 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Turning now to FIG. 1,there is shown an isometric view of one embodiment of the improvedcatalytic heater of this invention. The detailed description of theimproved catalytic heater will refer specifically to a portable heaterfor use in heating tents, duck blinds, garages, campers or otherrelatively small areas. However, it is to be understood that theprinciples discussed in the preferred embodiment can just as easily findapplication in larger catalytic heaters such as those used forindustrial purposes.

The catalytic heater generally noted as the numeral includes a frame 12having a hollow upstanding member l4'bordered at the lower end thereofby hollow horizontal members 16 and l8. Suitable legs 20are provided onthe underside of frame member 14 is a catalytic burner or bed assembly22 wherein fuel oxidation to produce heat occurs. A carrying handle 24hinged to upstandingframe member 14 possesses a positive stop whichprevents the handle from falling on or resting in front of the catalyticburner 22, thereby assuring a cool handle-at all times. Consequently theheater can be carried or repositioned at any time.

Referring now to the partial cross-sectional side view of FIG. 2, and inparticular to catalytic bed or burner assembly. 22, a support-materialretainer member 26 is pivotally connected to upstanding frame member 14and is bounded by a peripheral flange surface which receives and holds aplanar non-combustible supporting material 28 forming a catalytic bedsandwiched between wire-mesh 30 at the rearward surface of the:catalytic bed and wire mesh 32 at the forward surface of the catalyticbed. Non-combustible, supporting materialmay be of such materials asasbestos, silica gel or alumina and is,

saturated with a catalytic agent, such as platinum. A catalytic agent isa substance which alters the rate of chemical reaction between twobodies andis itself unchangedat the end of the reaction. For example inthe instantapplication, the platinum will alter the chemical reactionrate of hydrocarbon fuel and oxygen such that heat-producing oxidationwill occur at a temperature of approximately 800 F. which is below theflaming point of the fuel. Consequently catalytic heaters are used wherefire hazards must be minimized.

Received in upstanding frame member 14 is a commercially availablepressurized cylinder 34 of hydrocarbon fuel such as propane. Fuelcylinder 34 is inserted through an aperture in the bottom of upstandingframe member 14 and has a threaded neck which is screwed directly intothe receptacle of a pressure regulator 36 secured to the upper end offrame member 14. The receptacle of the regulator contains means forpuncturing cylinder 34 when such is received therein.

Spare fuel cylinders 34 are received in horizontal frame members 16 and18 and serve to make the heater tip-resistant. Legs 20 are pivotal as at38 to allow easy insertion and removal of the spare cylinders.

Pressure regulator 36 includes an outlet which feeds the inlet of amanually controlled metering valve 40 through suitable tubing 42. A knob44 projecting exteriorly of upstanding frame member 14 facilitates theopening and closing of metering valve 40.

The outlet port of metering-valve 40 is fluidly connected through tubing46 to the inlet of a safety needle valve 48 which is centrally securedto the back of retainer member 26 and which has the outletthereofpositioned so as to discharge fuel, when opened, onto supportingmaterial 28.

The opening and closing of valve 48 is controlled bythe sliding movementof valve needle 50 having a conicaltip 52 engageable in a pliant valveseat47 in the outlet port of valve 48. Needle 50 further includes anenlarged head portion 54 adapted to sprinkle fuel onto supportingmaterial 28 and a forwardly projecting stem 56 which passes throughanaperturein an aligning bracket 58 and terminates exteriorly ofsupporting material 28. The forward end of stem 56 is interconnected tothe lower end of a thermosensitive bi-metallic strip-60 having the upperend thereof rigidly interconnected to retainer member 26.

Needle 50 is biased toward valve seat 47 by means of a spring 62 sleevedover needle stem 56 and interposed between the needle head 54 and theforward leg of aligning bracket 58. Thus needle 50 will normally engagevalve seat 47 to shut off fuel flow; however upon heating,thermosensitive bi-metall ic strip 60overcomes the biasment of spring 62to disengage the needle from the valve seat to allow fuel to saturatesupporting material 28 whereat the reaction temperature heat-producingoxidation occurs.

Needle valve 40, needle 50 and bi-metallic strip 60 so disposed oncatalytic burner assembly provide for positive automatic fuel shutoflinthe event that during operation the catalytic bed temperature dropsbelow the value necessary for frame members 16 and 18. Pivotallyconnected to upstanding oxidation.

In addition to automatic fuel shutofi means, the catalytic heater ofthis invention also incorporates an ignition or pilot light apparatusfor preheating the catalytic bed 22 and bimetallic strip 60 to reactiontemperature without requiring the aforementioned step of sprinkling fuelon the bed. The ignition or pilot light apparatus includes a normallyclosed push button actuated valve 64 having an inlet port fluidlyconnected to the outlet port of metering valve 40 and having an outletport feeding through suitable tubing a pilot light noule 66. Acommercially available T-fitting 61 is one means of achieving theparallel connection of push button valve 64 and needle valve 48 to theoutlet port of metering valve 40. Nozzle 66 is disposed outwardly ofsupporting material 28 and is positioned such that a flame emanatingtherefrom will simultaneously heat the catalytic supporting material 28and bi-metallic strip 60. Push button valve 64 is to be located in aposition which is easily accessible to the operator of the heater.

Turning now to the operation of the catalytic heater of this invention,the heater is for operation that is lighted in the following manner.Metering valve 40 is opened by the use of knob 44 to allow gas to entertubing 46. Next the pilot light push button valve 64 is actuated, thatis, such is opened to allow gas to flow to nozzle 66 where an externalflame source, such as a match, is used to light the pilot light.

The flame emanating from the nozzle 64 simultaneously elevates thetemperature of the catalytic bed and bi-metallic strip 62. As thetemperature of the bi-metallic strip and the catalytic bed increases,valve needle 50 disengages to allow fuel to be admitted onto the supportmaterial 28 impregnated with the catalytic agent. At this point pilotlight valve 64 can be deactivated.

Initially fuel oxidizing on the catalytic burner will burn with arelatively small visible flame; however, after a short time, such as 30to 45 seconds, as the reaction temperature of the catalytic bed iselevated, the flame goes out and the oxidation proceeds without flame asfuel continues to be sprayed upon support material and to produceflameless heat.

In the detailed description of the preferred embodiments specificlanguage has been used for the sake of clarity. However, it is to beunderstood that such language is used for the sake of clarity only, anddoes not limit the invention in any manner.

What is claimed is:

1. A catalytic heater for producing flameless heat including safetyshut-off means, comprising:

a fuel supply;

a planar catalytic bed having a non-combustible support carrier and acatalytic agent thereon, the catalytic bed having a forward and arearward surface and having a small diameter opening therein;

a valve having an inlet port fluidly interconnected to said fuel supplyand to an outlet port;

a needle valve having an inlet port fluidly communicating with theoutlet port of said metering valve and an outlet port adapted todischarge fuel on to said catalytic bed rearward surface;

a valve needle slidably received in said opening in said catalytic bedand seatable in the outlet port of said needle valve;

spring means normally urging said needle valve to the closed position;and

a thermosensitive element supported adjacent the catalytic bed forwardsurface and interconnected to said valve needle, said thermosensitiveelement being positioned so as to be responsive to heat radiating fromsaid catalytic bed forward surface whereby upon heat radiating from saidbed forward surface said thermosensitive element disengages said valveneedle from said outlet port of said valve, and in the absense of saidheat, said spring moves said valve needle to seat in said needle valveto shut off fuel flow therethrough.

2. A catalytic heater as in claim 1 including a frame member supportingsaid catal tic bed, said frame includin an upstanding portion bordere atthe lower end thereof y horizontal members, said upstanding portionadaptable to carry said fuel supply in the form of a pressurizedreservoir, and including horizontal members containing therein at leastone spare fuel reservoir said spare reservoir serving as a stabilizer toreduce the possibility of tippage of said heater.

3. An apparatus as in claim 1 including an ignition means for preheatingsaid catalytic bed and thermosensitive element whereby said valve needledisengages said valve outlet port to permit discharging of fuel ontosaid catalytic bed for oxidation.

4. An apparatus as in claim 3 wherein said ignition means comprises:

a pilot valve having an inlet port fluidly interconnected to said fuelsupply and an outlet port; and

a pilot noule fluidly communicating with said pilot valve and positionedadjacent said catalytic bed forward surface and said thermosensitiveelement.

1. A catalytic heater for producing flameless heat including safetyshut-off means, comprising: a fuel supply; a planar catalytic bed havinga non-combustible support carrier and a catalytic agent thereon, thecatalytic bed having a forward and a rearward surface and having a smalldiameter opening therein; a valve having an inlet port fluidlyinterconnected to said fuel supply and to an outlet port; a needle valvehaving an inlet port fluidly communicating with the outlet port of saidmetering valve and an outlet port adapted to discharge fuel on to saidcatalytic bed rearwArd surface; a valve needle slidably received in saidopening in said catalytic bed and seatable in the outlet port of saidneedle valve; spring means normally urging said needle valve to theclosed position; and a thermosensitive element supported adjacent thecatalytic bed forward surface and interconnected to said valve needle,said thermosensitive element being positioned so as to be responsive toheat radiating from said catalytic bed forward surface whereby upon heatradiating from said bed forward surface said thermosensitive elementdisengages said valve needle from said outlet port of said valve, and inthe absense of said heat, said spring moves said valve needle to seat insaid needle valve to shut off fuel flow therethrough.
 2. A catalyticheater as in claim 1 including a frame member supporting said catalyticbed, said frame including an upstanding portion bordered at the lowerend thereof by horizontal members, said upstanding portion adaptable tocarry said fuel supply in the form of a pressurized reservoir, andincluding horizontal members containing therein at least one spare fuelreservoir said spare reservoir serving as a stabilizer to reduce thepossibility of tippage of said heater.
 3. An apparatus as in claim 1including an ignition means for preheating said catalytic bed andthermosensitive element whereby said valve needle disengages said valveoutlet port to permit discharging of fuel onto said catalytic bed foroxidation.
 4. An apparatus as in claim 3 wherein said ignition meanscomprises: a pilot valve having an inlet port fluidly interconnected tosaid fuel supply and an outlet port; and a pilot nozzle fluidlycommunicating with said pilot valve and positioned adjacent saidcatalytic bed forward surface and said thermosensitive element.